m(BaSO4) = 2.33*10^(-6) g
n(BaSO4) = 2.33*10^(-6)/233 = 1*10^(-8) mol
所以在100g水中,n(Ba2+) = n(SO4^2-) = 1*10^(-8) mol
所以c(Ba2+) = c(SO4^2-) = 1*10^(-8)/(100/1000) = 1*10^(-7) mol/L
Ksp = [1*10^(-7)]^2 = 1*10^(-14)